TNF and osteoporosis: Several studies have investigated the association between OS index and osteoporotic status.19,21, , –24 OS was further shown to be a powerful stimulant for the increased expression of the proresorptive cytokines such as IL-1, TNF-α, and IL-6, thus inducing osteoporosis.6,24 The postmenopausal female population is regarded as being even more vulnerable to OS not only because of old age but also by the lower level of 17β-estradiol (E2), which has been shown to act as an antioxidant.44